Rotary hook for sewing machines



July 4, 1944 v E. .1. BILLINGTON 2,352,598

ROTARY HOOK FOR SEWING' MACHINES Filed Sept. l2, 194D INVENTOR:

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mi BY e ATTORNEYS.

Pnt-nca Mya, 1944 j no1-Aar noon ron SEWING'Iim'ciminis` Emil J. Billington, Chicago,lll., assigner to Union Sdecial'Machine Company, Chicagmjlll., a corporation of'v Illinois lock stitch sewingn machines to cooperate withv the needles in stitch formation.

VIn rotary hooks `as ordinarily constructed, the non-rotating or bobbin housing-component isl restrained against rotation by a fixed engaging' element withprovision of suficient looseness for clearance by the front limb of the needle thread loop as the latter sweeps across th'e faceof the hook during each stitch-forming cycle; while the bobbin thread emerges through an egress opening at one side of the bobbin housing component Vand passes upward in contact with theface of the hook. As a consequence, 'owing to the loose play allowed the bobbin housing component, the latter is moved slightly in a direction opposite to that of the rotating or needle thread loop.

seizing component during each stitch forming cycle under the pull of the bobbin thread as the work is progressed by the feed ofthe machine.

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A slapping action thus takes place between the usual projection on the' xed rotation-restraining element of the machine and one side of the usual interengaging notch formed between the cheek projections on the flange face at the top of the bobbin housing component. This slapping restraining element associated with my improved rotary hook.

vWithi'nore detailed reference to the illustray tion, the numeral I0 designates the work support i of the sewing machine, which support has an apertureII for'passage. through it of a vertically reciprocating thread-carrying needle partially indicated at I2 in Fig. 1. The work support I0 also has slots I3 at opposite sides of the needle aperture II in the direction of feeding through which operate the upwardly-directed toothed projections I5 of a` feeding element. I6. This feeding element I 6 may be of the four motion type, and, in its action, intermittently advances the work W leftward in Fig. 1 as it is being stitched on the support I0. Y

At I1 is shown the presser vfoot of the machine which, during the feeding, reactsupon the feeding element I6 in a well known manner. Arranged to cooperate with the needle I2 in stitchformation below the work support I0 is a rotary hook which is comprehensively designated bythe numeral I8, said hook having an axially hollow action is not only objectionable from the standpoint of thenoise which it creates'especially when the sewing machine is operated at'high speeds, but alsoin that it promotes rapid wear `of the-parts. Moreover, the usual forms of rotary hooks are so constructed that the front limb of theneedle` thread loop in its sweep across the face of the hook during the stitch forming cycle, is obliged to contact over a considerable length with the bobbin thread. As a result, the movev ment of the needle thread loop around the bobbin case holder is impeded and its release correspondinglydelayed.

My invention has for its chief aim to overcome the foregoing drawbacks, which desideratum I attain in practice,* as hereafter more Vfully disclosed, through structural'changes in the hook, 'whereby, during eachstitch-forming cycle, the

loose playbetween the non-rotating or bobbin housing component and `the xed rotation-restraining element is effectively prevented, and through which the bobbin thread is controlled in such a manner as to obviate contact thereof with the outer limb of theneedle thread loop as the latter sweeps across the faceof the hook. Other objects and attendant advantages will appear from the following detailed description of the attached drawing, wherein Fig. 1 is a frag-V mentary view in cross section, of a lock stitch sewing machine conveniently embodying my in vention. Fig. 2 is a'view vin top plan looking asindicated by the angled arrows II--II in Fig. l; and

Iiig.` 3 shows the bottom view of the rotationrotating component I9 whereof the rearwardlyprojecting hub 20 is adjustably secured, by means' of set screws 2I, to the hook shaft 22, said com ponent having a needle thread lo'op-seizing'beak 23 and also a loop releasing horn 25. Disposed within the hollow of the rotating component I9 is a non-rotating component 26 which is likewise axially hollow and which has an interruptedcircumferential rib 21 in engagement with an internal circumferential groove 28 in said rotating component. Housed in turn within the hollow of the non-rotating component is a bobbin case 29 which contains a thread bobbin 30, which'lat- Y ter is mounted for free rotation about an axial stud 3i within the bobbin case. Through engagement of a. notch 32 at the top of the bobbin case 29 with a lug 33 internally of the component 26, said case is removably held in place with the aid of a retractable spring-influenced latch 35-which engages thestud 3I.` `The thread B of the bobbin 30 emerges through an aperture 36 at one side of the bobbin case 29 being drawn therefrom atV flange 40, the non-rotating component 26 of the hook is provided, according to my invention, with but a single cheek projection 4I, while the fixed rotation-restraining element or finger designated 42 is formed with a recess 43 between two lateral inward projections 44 and 45 for engagement by said projection 4I, the width of the recess being such as to afford sufficient clearance for the passage of the front limb of the needle thread loop as the latter sweeps across the face of the hook incident to stitch-formation. The finger 42 may be secured to the frame (not shown) of the sewing machine in any approved manner. It is to be noted from Fig. 1 that the cheek projection 4I is inclined somewhat to the vertical and, from Fig. 2, that said cheek is bevelled at the outer side to facilitate passage of the: outer limb of the needle thread over it from left to right in the drawing. By the frictional action of the rotating component I9 of the hook upon the non-rotating component 26, it will be seen from Fig. l that the projection 4I is at all times yieldingly urged 'against that side of the recess which is forward -in the direction of hook rotation by the frictional"k influence of the rotating component upon the" non-rotating component and the pull on the bobtoward the projection 44. It is to be further remarked that the inner side of the cheek projection is longitudinally recessed for the provision of a. groove 46 through which the bobbin thread reeres in its upward passage from the egress aperere 36 in the bobbin case 29 to the previouslyv .formed stitch in the work W. Consequently, during the interval incident to stitch formation when the work is being advanced leftward as shown in Fig. l by the action of the feeding element I6 with attendant pull on the bobbin thread B engaged in the notch 46 of the cheek projection 4|, said cheek projection is maintained in contact with the lug 44 of the rotation-restraining element 42. In this way it will be seen that the free rotative play normally of the component 26, is effectively prevented to the exclusion of any counterrotation and slapping of said component as occurs in the operation of rotary hooks of ordinary construction.

The groove 4S in the cheek projection also rforms another function, to wit, that of contro ng the bobbin thread B and keeping it retracted out of rubbing contact with the front limb of the needle thread loop L as said limb traverses said cheek projection in its sweep across the hook face.

'I'his feature of my inyention is of great advantage, not only in that it eases the movement of the needle thread loop around the bodyl of the bobbin housing component 26, but in that it obviates thread rupture. It therefore follows that a sewing machine fitted with my improved rotary hook can be safely operated at higher speeds than ordinarily, and that finer as well as cheaper threads can be used in it without danger of breakage.

The plane smooth surface left on the face of the flange 40 of the bobbin housing component resulting from the omission ,of the usual righthand cheek projection las at 41, also favors freer passage of the needle thread loop around said component. y

Having thus described my invention, I claim:

l. Rotary hook mechanism to cooperate with the reciprocating thread carrying needle and feed mechanism of a lock stitch sewing machine, comprising a rotary needle thread manipulating component; a frictionally engaged non-rotating bobbin thread component from a point at the periphery of which the bobbin thread is drawn in a direction opposite to the direction of rotation of the thread manipulating component; and rotation restraining means for the non-rotating compobin thread, for maintenance of a substantially constant interval between said projectionand the other side of the recess for free passage` of the needle thread as the stitch is being set at the complet-ion of each, stitch forming cycle.

2. Rotary hook mechanism according to claim l, in which the projection on the non-rotating component is notched to hold that portion of the bobbin thread which extends from the bobbin to a previously formed stitch in the work, so that said thread is held clear of the front limb of the needle thread loop as the latter sweeps across the face of said non-rotating component.

3. Rotary hook mechanism to cooperate with the reciprocating thread carrying needle and feed mechanism of a lock stitch sewing machine in which the work is intermittently advanced, said'mchanism comprising a non-rotating bobbin thread carrying component from a point at the periphery of which the bobbin thread is drawn in a direction opposite to the direction of rotation of the thread manipulating component; a rotating needle thread manipulating component revolving about said non-rotating component; and rotationrestraining means for the nonrotating component including a fixed element with a recess, and a projection on said non-rotating component loosely fitting in said recess, said v ing cycle when the stitch is being set, the nonrotating component is slightly shifted rotatively and the projection thereon is thereby urged P against the advance shoulder of the recess, for

maintenance of a substantially constant interval between said projection and the other side of said recess for free passage of the needle thread.

4. Rotary hook mechanism to cooperate with the needle of a lock stitch sewing machine,` comprising a rotary thread manipulating component; a :ion-rotating bobbin thread supply carrying component journaled in the rotary component; a rotation restraining member with a notch into which a projection on the non-rotating component extends, said projection being narrower than the notch, and, through rotation of the needle thread manipulating component caused to contact the stop shoulder at one end of the notch with maintenance of a clearance interval between it and the stop shoulder at the other end of the notch through which the needle thread loops can freely pass incident to release for stitch setting; and a guide provided in the projection through which the bobbin thread is drawn in a direction contrary to the direction of rotation oi the rotary component so as to assist in keeping said projection in engagement with the first mentioned of the two stop shoulders of the rotation 'restraining member.

EMIL J. BILLINGTON. 

